# Fulbat FTX4L-BS / FTZ5S-BS · Motorcycle battery 12V 4.2Ah 50A

![Fulbat FTX4L-BS / FTZ5S-BS · Motorcycle battery 12V 4.2Ah 50A](https://bateriasonline.es/642-home_default/fulbat-ftx4l-bs-ftz5s-bs.jpg)

> Fulbat FTX4L-BS / FTZ5S-BS: 4.2 Ah motorcycle battery, 50 A (EN), 113×70×85 mm, positive terminal on the right, AGM. Equivalent to Exide AGM12-4.

**Category:** [Motorcycle batteries](https://bateriasonline.es/en/motorcycle-batteries) → [Fulbat](https://bateriasonline.es/en/fulbat-batteries)

- **Canonical URL**: https://bateriasonline.es/en/fulbat-ftx4l-bs-ftz5s-bs
- **Language**: en
- **Brand**: Fulbat
- **Reference**: BOL-FULBAT-FTX4L-BS / FTZ5S-BS
- **MPN**: FTX4L-BS / FTZ5S-BS
- **Last updated**: 2026-10-27

## Technical specifications

| Feature | Value |
|---|---|
| Brand | Fulbat |
| Range | FULBAT Motorcycle MF |
| Application | Motorcycles |
| Technology | AGM |
| Voltage | 12 V |
| Capacity | 4.2 Ah |
| Cold cranking amps (EN) | 50 A |
| Length | 113 mm |
| Width | 70 mm |
| Height | 85 mm |
| Weight | 1.43 kg |
| Polarity | Positive terminal on the right |

## Quick description

Fulbat FTX4L-BS / FTZ5S-BS: motorcycle battery (AGM) with 12 V, 4.2 Ah and 50 A cold cranking current, measuring 113 × 70 × 85 mm, with the positive terminal on the right.

## Description

## The Fulbat FTX4L-BS / FTZ5S-BS at a glance

The Fulbat FTX4L-BS / FTZ5S-BS is a motorcycle starter battery: compact, vibration-resistant and with just the right power to turn the starter motor and feed the electronics. It handles frame vibration and idle periods better than an adapted car battery.
At 4.2 Ah it is a small battery, typical of 50 to 125 cc scooters and light motorcycles. The FTX4L-BS / FTZ5S-BS belongs to the Fulbat FULBAT Motorcycle MF range. [More Fulbat batteries](https://bateriasonline.es/en/fulbat-batteries)

## Equivalents and alternatives to the Fulbat FTX4L-BS / FTZ5S-BS

As the FTX4L-BS / FTZ5S-BS is an AGM battery, we only list other AGM batteries with its dimensions and polarity: neither an EFB nor a conventional battery can replace it.

| Model | Technology | Capacity | Cold cranking (EN) | Dimensions (mm) |
|---|---|---|---|---|
| Exide AGM12-4 | AGM | 3 Ah | 50 A | 115 × 70 × 85 |
| Exide ETX4L-BS | AGM | 3 Ah | 50 A | 115 × 70 × 85 |
| Varta YTX4L-4 (FA) | AGM | 3 Ah | 50 A | 113 × 70 × 87 |

## Fulbat FTX4L-BS vs FTX5L-BS

The real differences between the FTX4L-BS / FTZ5S-BS and the closest Fulbat models:

| Model | Capacity | Cold cranking (EN) | Dimensions (mm) | Positive | Weight |
|---|---|---|---|---|---|
| Fulbat FTX4L-BS / FTZ5S-BS (this one) | 4.2 Ah | 50 A | 113 × 70 × 85 | right | 1.43 kg |
| Fulbat FTX5L-BS | 4.2 Ah | 80 A | 113 × 70 × 105 | right | 1.78 kg |

- Fulbat FTX5L-BS: the same capacity, 30 A more cranking power, a different case (113 × 70 × 105 mm).

## What to look at before buying the FTX4L-BS / FTZ5S-BS

- The FTX4L-BS / FTZ5S-BS needs 113 × 70 × 85 mm of space: measure it with the hold-down clamp in place.
- With the terminals facing you, the positive terminal of the FTX4L-BS / FTZ5S-BS is on the right.
- Capacity of the FTX4L-BS / FTZ5S-BS: 4.2 Ah; the same as your current battery or slightly more is fine.
- The FTX4L-BS / FTZ5S-BS delivers 50 A cold cranking (EN standard); do not go below what your original battery states.

## Frequently asked questions about the Fulbat FTX4L-BS / FTZ5S-BS

### Fulbat FTX4L-BS / FTZ5S-BS or FTX5L-BS?

Compared with the FTX4L-BS / FTZ5S-BS, the Fulbat FTX5L-BS has 30 A more cranking power. If your current battery says 80 A or more, choose the FTX5L-BS; if it says 50 A or less, the FTX4L-BS / FTZ5S-BS is enough. Mind the space: the FTX5L-BS measures 113 × 70 × 105 mm.

### How much does the Fulbat FTX4L-BS / FTZ5S-BS weigh?

The FTX4L-BS / FTZ5S-BS weighs 1.43 kg. For reference, the Fulbat FTX5L-BS (4.2 Ah) weighs 1.78 kg.

### Which battery is equivalent to the Fulbat FTX4L-BS / FTZ5S-BS?

Only other AGM batteries with its dimensions and polarity: Exide AGM12-4, Exide ETX4L-BS and Varta YTX4L-4 (FA). Neither an EFB nor a conventional battery replaces the FTX4L-BS / FTZ5S-BS.

### Which side is the positive terminal on the Fulbat FTX4L-BS / FTZ5S-BS?

The FTX4L-BS / FTZ5S-BS has the positive terminal on the right, looking at the battery from its long side with the terminals closest to you.

## AGM technology in the FTX4L-BS / FTZ5S-BS

The FTX4L-BS / FTZ5S-BS is AGM: the electrolyte is absorbed in glass fibre mats, so it is sealed and spill-proof. Being sealed, the FTX4L-BS / FTZ5S-BS can be fitted in the boot or under a seat with no risk of spills.

## Keep comparing: alternatives to the FTX4L-BS / FTZ5S-BS

- [More motorcycle batteries](https://bateriasonline.es/en/motorcycle-batteries)
- [More Fulbat models](https://bateriasonline.es/en/fulbat-batteries)
- [Exide AGM12-4](https://bateriasonline.es/en/exide-agm12-4) · 3 Ah, 50 A, 115×70×85 mm
- [Exide ETX4L-BS](https://bateriasonline.es/en/exide-etx4l-bs) · 3 Ah, 50 A, 115×70×85 mm

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*bateriasonline.es — Batteries and accessories · 2026-11-11*